1. Field of the Invention
The present invention relates generally to the fields of immunoassay and chemical test devices that can be used to test for the presence of an analyte. In particular, the present invention relates to new procedural controls.
2. Background Information
Rapid lateral flow immunoassays and chemical test devices have an extensive history of use in both the clinical and the home settings. These devices are used to test for a variety of analytes, such as drugs of abuse, hormones, proteins, urine or plasma components and the like. The home pregnancy test, which requires a woman to urinate on a wick protruding from the test device and tells her if she is pregnant in a few minutes, is one such device with which many people are familiar.
These devices generally comprise a lateral flow test strip, such as nitrocellulose or filter paper, a sample application area, test results area and an analyte specific binding reagent that is bound to some kind of detectable label, such as a colored particle or an enzyme detection system. U.S. Pat. No. 6,485,982, U.S. Pat. No. 6,187,598, U.S. Pat. No. 5,770,460, U.S. Pat. No. 5,622,871, co-owned U.S. Pat. No. 6,565,808, and co-pending patent applications U.S. Ser. No. 10/278,676, U.S. Ser. No. 09/579,673 and U.S. Ser. No. 10/717,082, which are incorporated herein by reference, are non-limiting examples of such lateral flow test devices.
The present invention provides an improved procedural control, which indicates to the user that at least a portion of an applied sample solution has passed through the portion of the test strip upstream from the control zone, especially the test result zone, and optionally that the test is complete. At the completion of the test, the user may read the test results.